The announcement comes seven years after A Game Of Shadows – the second movie in the series – hit cinemas.

In an interview with Collider about his on-screen bromance with Law, Downey Jr. said: ‘Jude and I are pretty close, and Guy and I are practically brothers, which makes things really interesting.

‘There have been times when I’ve wanted to lop off his head with a machete, but it’s just because I love him so much.’

Whether director Guy Ritchie will be back to helm the project remains unknown. The 49-year-old filmmaker is currently working on Disney’s live-action remake of Aladdin. Then he’ll move on to finish production of Toff Guys – a gangster drama with a very British flavour.

‘When we announce the title I am not sure, but as I’ve probably said to you, it’s gotten completely blown out of proportion,’ he said.

‘It will just be a name and the reason to hold it back was to keep the attention on Infinity War. That backfired a little bit because now everyone thinks what’s the name of the next one gonna be? But it was really just to keep the focus [on Infinity War].’

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